def vote(self, block_id, previous_block_id, decision, invalid_reason=None):
"""Cast your vote on the block given the previous_block_hash and the decision (valid/invalid)
return the block to the updated in the database.
Args:
block_id (str): The id of the block to vote.
previous_block_id (str): The id of the previous block.
decision (bool): Whether the block is valid or invalid.
invalid_reason (Optional[str]): Reason the block is invalid
"""
if block_id == previous_block_id:
raise exceptions.CyclicBlockchainError()
vote = {
'voting_for_block': block_id,
'previous_block': previous_block_id,
'is_block_valid': decision,
'invalid_reason': invalid_reason,
'timestamp': gen_timestamp()
}
vote_data = serialize(vote)
signature = crypto.SigningKey(self.me_private).sign(vote_data)
vote_signed = {
'node_pubkey': self.me,
'signature': signature,
'vote': vote
}
return vote_signed
def __init__(self, transactions=None, node_pubkey=None, timestamp=None,
voters=None, signature=None):
if transactions is not None and not isinstance(transactions, list):
raise TypeError('`transactions` must be a list instance or None')
else:
self.transactions = transactions or []
if voters is not None and not isinstance(voters, list):
raise TypeError('`voters` must be a list instance or None')
else:
self.voters = voters or []
if timestamp is not None:
self.timestamp = timestamp
else:
self.timestamp = gen_timestamp()
self.node_pubkey = node_pubkey
self.signature = signature
def create_block(self, validated_transactions):
"""Creates a block given a list of `validated_transactions`.
Note that this method does not validate the transactions. Transactions
should be validated before calling create_block.
Args:
validated_transactions (list(Transaction)): list of validated
transactions.
Returns:
Block: created block.
"""
# Prevent the creation of empty blocks
if len(validated_transactions) == 0:
raise exceptions.OperationError('Empty block creation is not '
'allowed')
voters = self.nodes_except_me + [self.me]
block = Block(validated_transactions, self.me, gen_timestamp(), voters)
block = block.sign(self.me_private)
return block